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Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 05 Oct 2012, 17:38
by gilmour_pugliese
bajaman wrote:well here you go :lol:
resolution is 600 dpi :wink:
email me if you want higher res
cheers
bajaman
EMG DG20 combined SPC and EXG board.png



Any chance for a through-hole version of this? :popcorn:

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 07 Oct 2012, 10:10
by gilmour_pugliese
In the meanwhile, I've redrawn the scheme in Eagle...
If there's a hero which draws a tiny through-hole PCB, is welcome! :popcorn:

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 17 Feb 2014, 00:10
by rockstrana
Hello.

Anyone made this work?

I made spc control but something is wrong, I get only clean signal when pot is all the way up, exactly the same as bypassed.
I used substitute opamp - tl072 and ne5532, I found it can be substituted with those, could this be problem?

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 17 Feb 2014, 07:15
by alexradium
nope

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 21 Feb 2014, 00:21
by CHEEZOR
rockstrana wrote:Hello.

Anyone made this work?

I made spc control but something is wrong, I get only clean signal when pot is all the way up, exactly the same as bypassed.
I used substitute opamp - tl072 and ne5532, I found it can be substituted with those, could this be problem?

Does your build affect the sound at other points in the pot rotation or does it always sound like it is bypassed no matter the position of the pot? These circuits are designed so that when they are turned down to minimum, the signal sounds the same as bypassed (because there is no on/off switch for them when used in a guitar). You may have your wires to the pot backwards if turning clockwise decreases the affected signal.

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 23 Feb 2014, 13:56
by alexradium
gilmour_pugliese wrote:In the meanwhile, I've redrawn the scheme in Eagle...
If there's a hero which draws a tiny through-hole PCB, is welcome! :popcorn:
something like this?
its 31x40,single face,no links,space for cubic Panasonic caps.

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 25 Feb 2014, 21:49
by rockstrana
CHEEZOR wrote:
rockstrana wrote:Hello.

Anyone made this work?

I made spc control but something is wrong, I get only clean signal when pot is all the way up, exactly the same as bypassed.
I used substitute opamp - tl072 and ne5532, I found it can be substituted with those, could this be problem?

Does your build affect the sound at other points in the pot rotation or does it always sound like it is bypassed no matter the position of the pot? These circuits are designed so that when they are turned down to minimum, the signal sounds the same as bypassed (because there is no on/off switch for them when used in a guitar). You may have your wires to the pot backwards if turning clockwise decreases the affected signal.


It is possible I wired it backwards, but when turned it cuts volume, there is no any boost.

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 01 Mar 2014, 01:50
by CHEEZOR
alexradium wrote:something like this?
its 31x40,single face,no links,space for cubic Panasonic caps.

Yes, just like that. :) Thanks!

rockstrana wrote:It is possible I wired it backwards, but when turned it cuts volume, there is no any boost.

Its been a while since I have heard one these things, but I'm pretty sure there is supposed to be at least a slight boost... :S If you have some nice close up pics of your wiring I would post them to the troubleshooting section and see if someone can help you out. :thumbsup

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 17 Jun 2016, 23:02
by roseblood11
Bajaman,
in your first post you said that the SPC puts a 10db boost at 600hz. But on the EMG website, it says "6db boost around 1300hz" ?! :?: :?:

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 18 Jun 2016, 11:32
by roseblood11
My 10 year old SPC has a peak around 600Hz, so let's forget the statement about that 1.3kHz peak. I read that on the website of the german seller thomann.de, and it's most probably wrong.

But the picture of the SPC shows two more parts, that are not in the schematic: A capacitor and a diode or transistor, both close to the power supply wire. What are these for? Filtering or polarity protection?

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 18 Jun 2016, 17:25
by karul
roseblood11 wrote:But the picture of the SPC shows two more parts, that are not in the schematic: A capacitor and a diode or transistor, both close to the power supply wire. What are these for? Filtering or polarity protection?


They are present on the schematic - upper right corner. You're right - their purpose is filtering and polarity protection. Look at the bajaman's PCB, they are the same as EMG's.
There's one difference - 1k resistor is missing.

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 18 Jun 2016, 23:48
by roseblood11
Vero layout, small changes to the circuit for use with pasie pickups. I used a OPA2134, because the higher current draw doesn't matter for me, as I will add a true bypass pushbutton switch for the mid boost. Could be replaced with LF442, TL062, TLC2272 ...

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 19 Jun 2016, 12:41
by roseblood11
Is the circuit still the same in this version?
https://www.youtube.com/watch?v=eJG25PEsyLY
He puts the EXG before the SPC in the signal chain - with the input resistors shown on the schematics in this thread, this wouldn`t work with passive pickups...

Re: EMG DG20 (SPC and EXG) schematics etc.

PostPosted: 19 Jun 2016, 15:29
by karul
According EMG INSTALLATION INFORMATION :
The EXG has buffered inputs and can be used with passive pickups.